scholarly journals TWO-STEP CROSSLINKING OF PVP/GEL NANOFIBERS

2021 ◽  
Vol 2021 ◽  
pp. 164-170
Author(s):  
H.K. Güler ◽  
F.C. Çallıoğlu
Keyword(s):  
Fiber Diameter ◽  
Experimental Studies ◽  
Water Soluble ◽  
Diameter Distribution ◽  
Sem Images ◽  
Crosslinking Process ◽  
Different Temperatures ◽  
Ft Ir ◽  
Ir Analysis ◽  
Gel Polymers

In this study, it was achieved that crosslinking of PVP/GEL nanofibers with two-steps. Crosslinking is a process highly important for water-soluble polymers in terms of application areas and mechanical properties. Firstly, crosslinking of PVP polymers experimental studies were carried out via heat treatment at different temperatures and times. Then, GEL polymers were crosslinked with GTA vapour at different times. Morphological analysis was carried out via SEM images and chemical characteristics were determined via FT-IR analysis. Moreover, after the crosslinking process, SD and WL values were calculated. All results showed that before crosslinking of SEM images, nanofibers were smooth, fine and without beads. The average fiber diameter is 196 nm and the fiber diameter distribution is quite uniform. After crosslinking of SEM images, it is expected that all nanowebs will turn from fibrous surfaces to membranous. Generally, SD and WL values decrease with crosslinking time increase. According to all of the SEM images, SD and WL values, optimum conditions were determined for PVP as 4 hours at 180oC and for GEL as 24 hours. Lastly, the presence of PVP and GEL polymers in the nanofiber structure was verified chemically with FT-IR analysis.

scholarly journals A Sulfur Copolymers (SDIB)/Polybenzoxazines (PBz) Polymer Blend for Electrospinning of Nanofibers

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1526 ◽  
Author(s):  
Ronaldo P. Parreño ◽  
Ying-Ling Liu ◽  
Arnel B. Beltran
Keyword(s):  
Polymer Blend ◽  
Single Phase ◽  
Fiber Diameter ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Sem Images ◽  
Water Contact ◽  
Fixed Concentration ◽  
New Material ◽  
Nanofiber Mats

This study demonstrated the processability of sulfur copolymers (SDIB) into polymer blend with polybenzoxazines (PBz) and their compatibility with the electrospinning process. Synthesis of SDIB was conducted via inverse vulcanization using elemental sulfur (S8). Polymer blends produced by simply mixing with varying concentration of SDIB (5 and 10 wt%) and fixed concentration of PBz (10 wt%) exhibited homogeneity and a single-phase structure capable of forming nanofibers. Nanofiber mats were characterized to determine the blending effect on the microstructure and final properties. Fiber diameter increased and exhibited non-uniform, broader fiber diameter distribution with increased SDIB. Microstructures of mats based on SEM images showed the occurrence of partial aggregation and conglutination with each fiber. Incorporation of SDIB were confirmed from EDX which was in agreement with the amount of SDIB relative to the sulfur peak in the spectra. Spectroscopy further confirmed that SDIB did not affect the chemistry of PBz but the presence of special interaction benefited miscibility. Two distinct glass transition temperatures of 97 °C and 280 °C indicated that new material was produced from the blend while the water contact angle of the fibers was reduced from 130° to 82° which became quite hydrophilic. Blending of SDIB with component polymer proved that its processability can be further explored for optimal spinnability of nanofibers for desired applications.

scholarly journals Lignosulfonate and silica as precursors of advanced composites

2013 ◽  
Vol 15 (3) ◽  
pp. 103-109 ◽  
Author(s):  
Łukasz Klapiszewski ◽  
Magdalena Nowacka ◽  
Katarzyna Siwińska-Stefańska ◽  
Teofil Jesionowski
Keyword(s):  
Paper Industry ◽  
Polar Medium ◽  
Sem Images ◽  
Waste Products ◽  
Advanced Composites ◽  
Ft Ir ◽  
Colorimetric Study ◽  
Ir Analysis ◽  
Parameters Of Porous Structure

Abstract Advanced silica/lignosulfonate composites were obtained using magnesium lignosulfonate and silica precipitated in a polar medium. For comparative purposes analogous synthesis was performed using commercial silica Aerosil®200. Lignosulfonates are waste products of paper industry and their application in new multifunctional materials is of great economic interest. The composites obtained were subjected to thorough characterization by determination of their physicochemical, dispersive-morphological and electrokinetic properties. Their particle size distribution was measured, SEM images were taken, FT-IR analysis and colorimetric study were made, thermal and electrokinetic stabilities and parameters of porous structure were also determined. The results can be of interest in further application studies

Characterizations of Newly Fabricated Composite Materials Based on Organoclay Incorporated Polymeric Matrix

2017 ◽  
Vol 902 ◽  
pp. 79-82
Author(s):  
Bhajan Lal ◽  
Attaullah ◽  
Shafique Ahmed Arain ◽  
Sajid Haleem ◽  
Sagar Kumar
Keyword(s):  
Composite Materials ◽  
Polyacrylic Acid ◽  
Characteristic Peak ◽  
Sem Images ◽  
Porosity Distribution ◽  
Infra Red ◽  
Ft Ir ◽  
Organic Clay ◽  
Ir Analysis ◽  
Scanning Electron

This article reports the synthesis of engineered materials i.e. composite materials based on matrix (polymeric polyacrylic acid) and reinforcement (organic clay) through 6-hour and 12-hour ultrasonication at different intervals. All the precursors and desired composite materials were characterized by Fourier transform infra-red (FT-IR) and scanning electron microscopy (SEM) techniques. The disappearance of Si-O characteristic peak after ultrasonication justifies the fabrication and incorporation of organoclay in the polymeric structure of polyacrylic acid as revealed by FT-IR analysis. The SEM images interpreted the surface morphology, porosity, distribution and compatibility of matrix and reinforcement in it, which has been achieved successfully in this study for exfoliation form.

scholarly journals ELECTROSPINNING OF ST. JOHN'S WORT OIL LOADED MICROCAPSULES BASED PVA NANOFIBERS

2021 ◽  
Vol 2021 ◽  
pp. 171-177
Author(s):  
H.K. Güler ◽  
F.C. Çallıoğlu ◽  
İ.Y. Mol ◽  
M. Geysoğlu
Keyword(s):  
Surface Tension ◽  
Smooth Surface ◽  
Fiber Diameter ◽  
Experimental Studies ◽  
Optimum Process ◽  
Sem Images ◽  
Eudragit Rs ◽  
Uniformity Coefficient ◽  
St John’S Wort ◽  
St John's Wort

In this study, it was achieved that the production of St. John's Wort oil loadad Eudragit RS 100/PVA microcapsules by emulsion/solvent evaporation method and the microcapsules were embedded in PVA nanofibers. Morphological analysis was carried out with SEM images of both microcapsules and nanofibers. The presence of St. John's Wort oil, PVA and Eudragit RS 100 polymers were confirmed in the chemical structure of microcapsules and nanofibers by FT-IR. According to experimental studies, microcapsules were produced to have a smooth surface, a spherical shape and a uniform particle size. The PVA concentration was kept constant at 10% wt and microcapsule concentrations were applied as 1, 3, 5, 7, and 9 wt %. Then, polymer solution properties were measured, such as conductivity, viscosity, and surface tension. It was determined that viscosity and surface tension values increased with microcapsule concentration increase, while conductivity did not change significantly. Nanofiber production was realized via the electrospinning method under the optimum process parameters. According to the SEM images and histogram, nanowebs have a fine fiber diameter, smooth surface, high quality and no bead structure. In addition, the average microcapsule size is 30 μm, average fiber diameter is 430 nm and the fiber diameter uniformity coefficient is 1,014. It is thought that this nanofiber surface containing microcapsules embedded in St. John's Wort has the potential to be used as a wound dressing.

scholarly journals Green Hydrothermal Synthesis of N-doped Carbon Dots from Biomass Highland Barley for the Detection of Hg2+

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3169 ◽  
Author(s):  
Xie ◽  
Cheng ◽  
Liu ◽  
Han
Keyword(s):  
Carbon Dots ◽  
Limit Of Detection ◽  
Amorphous Structure ◽  
Water Soluble ◽  
Diameter Distribution ◽  
High Quantum Yield ◽  
N Doping ◽  
Ft Ir ◽  
Doped Carbon Dots ◽  
Highland Barley

Totally water-soluble N-doped Carbon dots (N-CDs) were synthesized by a green hydrothermal method from biomass using Highland barley as a carbon source and ethanediamine as nitrogen source. TEM and XRD showed the graphitic amorphous structure and narrow diameter distribution of these N-CDs. N-doping to the crystal lattice and carrying many hydrophilic groups on the surface of N-CDs were verified by XPS and FT-IR. The as-synthesized N-CDs emitted strong blue fluorescence at 480 nm and owned a relatively high quantum yield of 14.4%. The product also could sensitively and selectively detect Hg2+ ions in the range of 10–160 μM and the limit of detection was equal to 0.48 μM.

scholarly journals Analytical Characterization of an Inulin-Type Fructooligosaccharide from Root-Tubers of Asphodelusramosus L

2021 ◽  
Vol 14 (3) ◽  
pp. 278
Author(s):  
Valentina Noemi Madia ◽  
Daniela De Vita ◽  
Antonella Messore ◽  
Chiara Toniolo ◽  
Valeria Tudino ◽  
...  
Keyword(s):  
Degree Of Polymerization ◽  
Water Soluble ◽  
Extensive Literature ◽  
Alkaline Extraction ◽  
Alkaline Extract ◽  
Therapeutic Uses ◽  
Ft Ir ◽  
Ir Analysis ◽  
Phytochemical Studies

Plant-based systems continue to play a pivotal role in healthcare, and their use has been extensively documented. Asphodelus L. is a genus comprising various herbaceous species, known by the trivial name Asphodelus. These plants have been known since antiquity for both food and therapeutic uses, especially for treating several diseases associated with inflammatory and infectious skin disorders. Phytochemical studies revealed the presence of different constituents, mainly anthraquinones, triterpenoids, phenolic acids, and flavonoids. Although extensive literature has been published on these constituents, a paucity of information has been reported regarding the carbohydrate composition, such as fructans and fructan-like derivatives. The extraction of water-soluble neutral polysaccharides is commonly performed using water extraction, at times assisted by microwaves and ultrasounds. Herein, we reported the investigation of the alkaline extraction of root-tubers of Asphodelus ramosus L., analyzing the water-soluble polysaccharides obtained by precipitation from the alkaline extract and its subsequent purification by chromatography. A polysaccharide was isolated by alkaline extraction; the HPTLC study to determine its composition showed fructose as the main monosaccharide. FT-IR analysis showed the presence of an inulin-type structure, and NMR analyses allowed us to conclude that A. ramosus roots contain polysaccharide with an inulin-type fructooligosaccharide with a degree of polymerization of 7–8.

The Structure and Properties of Sulfo-Butylated Celluluse Ether (SBC) Based Water-Reducing Agents

2014 ◽  
Vol 556-562 ◽  
pp. 433-440
Author(s):  
Halidan Maimaiti ◽  
Xuekelaiti Aerken
Keyword(s):  
Cement Paste ◽  
Water Soluble ◽  
Crystalline Cellulose ◽  
Cellulose Ether ◽  
Hardened Cement ◽  
Structure And Properties ◽  
Hardened Cement Paste ◽  
Sem Images ◽  
H Nmr ◽  
Ft Ir

Abandoned cellulose was treated with acid to prepare Micro-Crystalline Cellulose (MCC) holding affirmative polymerization, which was then treated with 1,4–butanesultone (BS) to synthesize water-soluble Sulfo-Butylated Cellulose ether (SBC). The structure of the SBC was characterized by means of FT-IR, 1H NMR, SEM, and XRD, and its relationship to function was investigated based on the polymerization of MCC and Degree of Substitution (DS). SEM images of hardened cement were also studied. The results indicated that when the polymerization of the MCC was smaller than 96 and the DS greater than 0.375, SBC exhibited water-reduction. When sulfonated cellulose was mixed into the cement paste, its retarding effect slowed hydration early in the aging process, so that later the structure of hardened cement paste became more uniform and compact than that of control.

Fabrication and Characterization of Electrospun Polysulfone (PSF)/Organo-Montmorillonite (O-MMT) Nanostructured Membranes

2018 ◽  
Vol 916 ◽  
pp. 125-129 ◽  
Author(s):  
Ruth R. Aquino ◽  
Marvin S. Tolentino ◽  
Joren V. Angeles ◽  
Hershey Azelle Millano
Keyword(s):  
Mechanical Properties ◽  
Fiber Diameter ◽  
Polymeric Membranes ◽  
Fiber Morphology ◽  
Ft Ir ◽  
Ir Analysis ◽  
Fabrication And Characterization ◽  
Nanostructured Membranes ◽  
Mmt Clay

Polymeric membranes infused with clays have attracted researchers for it poses a great potential in water treatment applications. In this study, polysulfone (PSF) has been infused with organo-montmorillonite (O-MMT) clay to fabricate membranes through electrospinning and were subjected into different characterizations to find out the effect of adding the clay to the polymer.Four sampleswith different amounts of O-MMT have been fabricated (Pure PSF, 1% O-MMT, 3% O-MMT and 5% O-MMT). The fiber morphology, fiber diameter,surface chemical composition, hydrophobicity, and mechanical properties of these samples were studied. Preliminary investigationhas revealed that shallow pores and smaller fiber diameter were formed with increasing O-MMT concentration. Molecular interaction between the PSF and O-MMT was also revealed through the FT-IR analysis. With regards to contact angle, there are no significant differences between the measurements for each PSF/O-MMT blend. Improvements in the mechanical properties of the samples were also observed as the O-MMT concentration increases.

scholarly journals Removal of Siloxanes from Model Biogas by Means of Deep Eutectic Solvents in Absorption Process

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 241
Author(s):  
Edyta Słupek ◽  
Patrycja Makoś-Chełstowska ◽  
Jacek Gębicki
Keyword(s):  
Experimental Studies ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Tetraethylene Glycol ◽  
Absorption Process ◽  
Molar Ratios ◽  
Screening Model ◽  
Tetrapropylammonium Bromide ◽  
Ft Ir ◽  
Ir Analysis

The paper presents the screening of 20 deep eutectic solvents (DESs) composed of tetrapropylammonium bromide (TPABr) and glycols in various molar ratios, and 6 conventional solvents as absorbents for removal of siloxanes from model biogas stream. The screening was achieved using the conductor-like screening model for real solvents (COSMO-RS) based on the comparison of siloxane solubility in DESs. For the DES which was characterized by the highest solubility of siloxanes, studies of physicochemical properties, i.e., viscosity, density, and melting point, were performed. DES composed of tetrapropylammonium bromide (TPABr) and tetraethylene glycol (TEG) in a 1:3 molar ratio was used as an absorbent in experimental studies in which several parameters were optimized, i.e., the temperature, absorbent volume, and model biogas flow rate. The mechanism of siloxanes removal was evaluated by means of an experimental FT-IR analysis as well as by theoretical studies based on σ-profile and σ-potential. On the basis of the obtained results, it can be concluded that TPABr:TEG (1:3) is a very effective absorption solvent for the removal of siloxanes from model biogas, and the main driving force of the absorption process is the formation of the hydrogen bonds between DES and siloxanes.

Characterization and Properties of Antheraea pernyi Silk Finished with Reactive Quaternary Ammonium Salt of Chitosan

2011 ◽  
Vol 175-176 ◽  
pp. 288-293 ◽  
Author(s):  
Yan Hua Lu ◽  
De Hong Cheng ◽  
Zhao Dan Yang
Keyword(s):  
Ammonium Salt ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
Silk Fiber ◽  
Water Soluble ◽  
Chitosan Derivative ◽  
Sem Images ◽  
Antheraea Pernyi ◽  
Before And After ◽  
Ft Ir

In order to obtain a water soluble and reactive chitosan derivative, quaternary ammonium salt groups and acrylamidomethyl groups were introduced to chitosan by two steps. The chitosan derivative, reactive quaternary ammonium salt of chitosan, was then applied to Antheraea pernyi (A. pernyi) silk by padding and curing method. FT-IR, XRD and SEM were used to characterize the structure of A. pernyi silk before and after treatment. The peak in FT-IR spectra at 1480 cm-1 and 1650 cm-1 revealed the crosslinking reactions of A. pernyi silk fibroin and reactive quaternized chitosan. The XRD results indicated the crystallinity of the treated silk fiber increase a little in comparison with the untreated ones. SEM images clearly showed the reactive quaternary ammonium salt of chitosan attached on the surface of the treated A. pernyi silk fiber, while the surface of the untreated sample was relatively smooth. The thermal stability of the treated silk fiber was enhanced compared to the untreated one by DSC analysis. It was also found that the antibacterial activity of the treated A. pernyi silk fabric against E. coli was more than 99%.

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